Composite article and method of making same



Aug. 16, 1932. T. FREDERICK COMPOSITE ARTICLE AND METHOD OF MAKING SAME Filed April 17,- 1926 2 Sheets-Sheet l JUGQZOP ows ZfiEDER/CK 1932- L. T. FREDERICK 1,872,269

COIPOSITE ARTICLE AND METHOD OF MAKING SAME Filed April 17, 1926 2 Sheets-Sheet 2 fl l5 .5 W 62 170 I E 70 1/ g0] 66 W 15' "My (J4 "PM U Patented Aug. 16, 21932 TE JSTATEs- PATENT oFncEf LOUIS T. FREDERICK, OF VAIIPARAISO, INDIANA, ASSIGNOB, BY ASSIGNMENTS; I

TO CONTINENTAL. DIAMOND IIBRE COMPANY, '01 NEWARK' A COR- DURATION OF DELAWARE p I cmosrrn ARTICLE Am mnrnon or MAKING sum Applmaticnflled April 17,

In general'my'invention relates to a process for formin "a ractically homogeneous and substantial y rigid article from superposed sheets or lammations of semi plasti'c' material. In; one of its aspects ,my process includesthe drawing or pressing ofthe sheets into a finished article having a circumferen- I ameters for permitting the sheets when drawn or pressed by the dies to-fiow or stretch into a finished article of substantially uniform cross section and requisite strength. The in-' vention also includes the article made by my roce'ss; Inyparticular I have illustrated my invention as applied to mica insulatingrings and to the method of making them. These ringsare intended primarily forthe commu-- tators of dynamo electric machines, and the general object of the invention is to produce a ring which shall have high and uniform insulating properties, possess high mechanical strength, and be economical to manufacture. I L v I obtain this object in'the manner illustrated in the accompanying. drawings, in.

which I c Figure 1 illustrates the finished article, a section being'broken" away toashow'the in ternal construction.

' Figure 2 represents a set of discs from which the ring is produced, these beingshown spaced apart for the purpose of illustrating their individual construction and their relationship' to each other in assembly.

Figure 3' is a fragmentary sectional view" taken through the flanges of one of therings to show on an enlarged scale the final relationship of the parts.' I

Figures 4, 5 and 6'show the progressive steps of manufacture in a forming machine or press;

Like numerals denote like out the several views. v

I will describe a typical instance Qfthe parts through 1926., Serial no. 102,820.

process and product in order that theprinciple of the invention may be understood In aftypical case the work'material is mica plate, a known article consisting of flakesv of ,micaflaid in overlapping relation and bound together by shellac or. other suitable binder. Thismicaplatehas high insulating property,electrically, and it is my purpose to produce from it a ring which is strong mechanically and whose dielectric properties are uniform throughout its surface; This" micaplate is produced in sheets andis semi plastic when hot. 7 I

To described the process in its developed form; I first prepare a plurality of discs or completesheets 10, 11,12,113 of mica plate] 1 as'illustrated in Figure complete sheets 'I mean a sheet which is coextensivewith the entire surface of the ring'in distinction to seetors of thering. These discsmay-be varied in number, size andcharacter, but Il'am describing'a typical example. allv perforated at the center so that they may fit over a centering pin 16 shown in Figures 4; to 6 and hereinafter,again referredto. In the f 'orm'shown the lowermost disc 13 isunslitted. Above this Iplace adisc 12of larger diameter and having anumber of slits 18- runningin from the periphery. These slits are in the formof line-like incisions as distinguished from sectors, notchesor slots, which later form relativelyextensive cut-out portions, the differencein function between my line-like incisions and the slots ornotches being that whenmy slitted discs are drawn as hereindisclosed the adjacent edges ofthe slits of each disc or sheet arecaused to overlap, thereby permitting suflicient contraction of the peripheral or outer portions of the sheet; In the case ofjthe' sheets having sectors or notches or substantial cutouts the adjacent edges of the cutouts merely abut upon I pressing or drawing, in the contracting operation. They do not overlap. By preference these do not run radially but at an oblique angle to a radius Above this I place a disc 11'0f somewhat larger diameter and having slits ,18 similar to the slits of disc 12.

Above disc 11' is placed a disc 10 which is 3 The discs are.

of smaller diameter than disc 13 and is unslitted.

These discs are superposed in the order described in the forming machine, whose chief portions are illustrated in Figures 4 to 6. Referring to the machine itself, there is a sta tionary recessed die 20, the walls of which converge lightly in a downward direction to produce the final product shown in Figure 1, viz. the completed ring having an external flange 22 and the internal flange 24. The discs are centered over the pin 16 previously mentioned, whi h pin rises from a stationary cylindrical core 26. The upper rim 28 of the recessed die 20 is rounded and there is also a rounded shoulder 30 at the bottom of the recess.

Cooperating with the recessed die is a projecting die 32 which in general form is a hollow cylinder and has a lower periphery in.

the form approximately of a rounded V. This projecting die diverges upward from the lower periphery at a pitch corresponding to the pitch of the walls ofthc recessed die 20. Its inner diameter is substantially equal to the external diameter of the center core 26, thus making a sliding fitupon it and serving as a cut-off in cooperation with the upper periph eral shoulder of said core. It is reciprocated vertically by suitable means.

The press or former also has an ejector die 34, which is annular in form and is also reciprocated vertically with the proper timing which will be hereinafter described. The mechanism for operating it need not be here described, as the press forms no part of my present invention but is shown and described in a copending application filed by me on the 11th day of November, 1926, Serial No. 147.710. 7

The ejector die surrounds and is guided by the center core 26 and when in lowermost position as shown in Figures 4, 5 and 6 it constitutes the bottom of the chamber in which the ring is formed. It has a conical upper surface 36 which cooperates with the correspondingly beveled surface 38 at the lower rim of the projecting die 32.

By preference the projecting die 32 has an annular shoulder 40 at the top of the acting portion, viz. the point corresponding to the top of the finished ring. This shoulder serves to finish the ring and also to cut oil any surplus material in case the discs of work material are too large for the work in hand.

In practicing the process, after the discs are formed as previously explained, they are placed one upon another in the machine in the manner shown in Figure 4. They rest upon the top of the recessed die 20 and are held centered by the pin 16. After the discs are thus positioned the projecting die 32 commences to descend, and as it does so it bends the work sheets in the manner shown in Figure 5. The lower rim of the die forces U16 engaged portions of the discs downward faster than the adjacent portion, and as the die approaches its lowermost position it cooperates with the upper annular shoulder of the core 26 to sever the central portion of the disc from the remainder which is to form the ring. This action is illustrated in Figure 6 which shows the projecting die in lowermost position and'the ring in its final form.

The sheets are hot when they are put into the press, and hence are plastic to a considerable degree. In the illustrated case where four sheets are employed the uppermost sheet is of a diameter but slight-1y larger than the diameter of the lower rim of the projecting die 32. The other discs are larger than the diameter of the recess in the die 20 and are arranged with a disc of larger diameter above one of smaller diameter. Of course it will be apparent that I am not limited to the use of any particular number of discs, and that it may be desirable, especially where rings of small size are to be made, to use only two superposed discs, i. e., the upper discs 10 and 11, or three discs in which case discs 10 and 11 may be used with either a slotted disc similar to disc 12 or an unslotted disc similar to disc 13. I have also discovered that rings of small size and dimension may be successfully made of two superposed discs without slotting the periphery of the larger disc since the peripheral portions of the disc do not tear or rupture during the folding process. The diameter of the slotted disc 11 is such that as the die descends the outer periphery will come somewhat beneath the shoulder 40. The periphery of the slotted disc 12 next below will, in the beginning come somewhat lower down and the periphcry of disc 13 next below will come still further down as shown in Figure 5. As the projecting die descends the outer annular portion of the slotted discs 11, 12 will not only be pressed toward each other radially but will be also contracted circularly and simultaneously caused to slip upon each other until finally the parts assume the relation shown in Figure 6 in which the upper, outer rim of the discs will come flush with each other and into contact with the shoulder 40. Thus there is a consolidating, contracting and slipping action and the slitted portions of the discs 11, 12 are caused to overlap each other, thus permitting the parts to become co-adjusted and to assume the final form shown. It will be noted that the unslotted disc '13 does not slip entirely up to the top of the mold as does the slotted disc 12, but is squeezed out partially as shown clearly in the enlarged sectional view in Fig. 3. It should be understood that the pressing operation flows the discs into a homogeneous article in which there are no plans of cleavage and the showing of such plans in the drawings of the final object being merely the material f use discs. The $0. 40

finishes the upper of rin and will out fi-a yu p u ,11m: flw be present by squeezing it out into a: groove 41 formedin-ltherwall ofitheadiaflir Itia also evident thatv by my method ofloentering' the sheets by gauging; them from the margins of their central apertures in ,distinctim from their peripheral. margins, those; outer: edges of thetsheetsare freedlui g z thedrawing and pressing-1 operation so that they; are. to register or form a iedgeof the flange,

the edge being formed of the conterminous edges of, thevarious sheets originally wene'of-difierent diamctom sto'theinnerIiflangeQQoflthQ ring, Ia stretching action seems :totake plow,

with the resultthatin. spiteof the, of the ;-additional; r 1;) the finished inner flange of: the: ring willbc, no thickerthan the plastic :andselecting the sizes-and construe-r tion'of work sheetsshownpandpressing them in, amold of thischaracter withonter walls which diverge outward and inner walls which converge inward the work sheets ad.-v just themselves and 'i become consolidated in a ring which istwo -plyi atthe-topvand three ply at the base ofgthe outer flange and tour ply at the i n-nerflange: and. yet of approximatelythe same: thickness at I all points of; both; fla es It willl bo-understood th t when the iscs, are placedi'in the machine one}, is taken not to have-thsslits of one-discovew lyingtheyslits of the adjacent one. Tharresuit is that the slits do not register the finished article and inviaetthe edges Yap-pars ently overlap at these, pointsg-andi hence" the;

slits do not weaken the ringalthongbthey permit the mutual; adjustment, and: flowing, so to speak, ofthe' material of; which-the work;

sheetsare, formed. This-has been "found" to produce a ring: of: great mechanical stnength;

and one in which the dielectric: properties are quite uniform over the surface, thus prevent ng electrical penetration any more;eas=

ily at one point than at another. ffllilli'r ing the slits-18 inythe discslland 12' non radially, it disc 11 when superposed" on disc 12 be reversed in its arrangement vso that' the. incisions 18 extend ina directionoppositeto thosein the disc v12,or in" other words, if

one of'these discs. be turned over from the position shown in Figureflrandthen supew posed on the other. when the pressing ,operation takes place the incisions will liecrises" ross and-Q QIQI'Z IQ c nn t pos bly s me nw fution will not be present; hence the ind Va ofanont-radid inoisimrsr It will: be: understood; number of ,dims may heavmried,. andztlwt other maodific'atiaonsmay'be made in the process'without w oeedingtlmscope of the: invention, which is setzout inthe appended claims. i

7 Having thus described my invention what vI claimas new and desire to secure by compacting their peripheral portions meansiofrpressune exertediedgswise on said peripheral} portions. 7 l

2. The method-zof maliing; laminated imm semi-plastic micasheets consisting; in

taking; sheets of unequal. sine,v aligning the sheets coaxially one above-thaothenandform ring shcetsintoa receptacle: hawing con- Yei'ghgaides for; consolidatinyi;the:sheets and simultaneously compacting their" peripheral portionsiby meanaof pressnre emertod edgewise: on said peripheral portions;

The methods; of making: lted rings consisting preparing; a. plurality ofdiscs.

of difi'erent diameter, flitting; their peripher al-i portions, -pl-acing. them coaxially; one ahovethe other with arsheet' of smaller dime ter below a sheet of larger diameter, bending the: peripheral portions ofthe sheets upwardly, trout-"their original plane,- aznda simultm neously exerting: pressure, consolidatingithe sheets and. compacting the periphrerail POPt lOIL by means of pressure". exe edgewise on said .j eripheml. portions mom closely. 1 i Y r 4. The method of making: laminated: consisting; in; peeps ring circular sheets of mica platerofl different diameters, makingslits in the peripheral portiomoi the sheets ex! tending nonrnadially, heating the sheets; to

vremierf them semi-plastic, super-posing: the

sheets. concentrically, bending; the sheets; along a circleeoneentric with but spacedfrom the circumference of the sheets to form: outer flange extending obliquely to'the 7 plane of thev ring, and pressing; the sheets together to consolidate them.

5. The method'of making laminated insnlating'rings consistingjin reparing'cirrula-r sheetsofmi'caplate of di erent diameters, heating them to" nenden semi-plastic, super-posing? the sheets: concentrically, bendmg the sheetsalong a cirelerconcentric with:

but spaced from the circumference of, the: dleets to form anrouterflknge extending 0bliquely to the plane of the-ring, pressing thesheets together to consolidate the-m, andialso compacting the: upper outer the ring im-r limdializieisiunsbeamdthis by means of edgewise and finish the same. i

6. An insulating ring approximately V shaped in cross section and composed of a plurality of layers consolidated to ether, some of the layers having slits exten ing to the outer periphery and arranged inv a nonradial direction,-the slits of one layer being out of register with the slits of the adjacent layer.

7 An insulating ring for commutators consisting of a plurality of laminations of mica plate approximatelyV shaped in cross section, the 'laminations being pressed together and consolidated and the inner flange having a greater number oflayers than the outer flange and being of approximately the same thickness. i l 8. An insulating ring for'commutators consisting of aplurality of laminations of mica plate approximately 'V-shaped in cross section, the being rounded at the bottom, the laminations being consolidated and the inner flange having a greater number of layers than the outer flange, the excess layer of the inner flange rounding the point of the V for reinforcing it there.

9. The method of 1' making insulating bodies which includes concentrically superposing a plurality of layers of circular mica sheets, some of which are of different diameters and subjecting them while hot to the action ofa drawing die andpunching out the central portion of the sheets during the die drawing operation. i

10. The method of making insulating bodies which includes concentrically superposing a plurality of circular mica sheets, one of which is of larger diameter than another, and subjecting the sheets while hot to the action of a drawing die and punching out the central portion of the sheets during the die drawing operation.

11. The herein described method which coin rises superposing a plurality of mica discs ofdifferent diameters disposed in coaxial registration,*holding the central portions of the discs while subjecting intermediate portions thereof to'a" die pressing action to drawthe same and cause the registration or" the peripheral portions of said-discs wherebyito form an artiole of substantially uniform cross section and punching outthe held central portion at the conclusion of the drawing operation. I

- 12. A mica insulation ring substantially V- shaped in cross section and having flanges composed of a plurality of superposed layers of mica pressed into a'substantial homogeneous mass, one of the flanges of the ring having a'greater number of layers than the other.

13. A mica insulating member composed of a plurality of superposed sheets of mica die pressed and drawn into desired cross section, a certain part of said cross section bepressure to consolidate ing composed of more layers than another 'art.

14. The method of making mica insulating rings having intersectin flanges, consisting inpreparing washers o mica plate, centering them by holding them at the center hole of the washers, heating the washers, die pres sing them to form the two flan s, and the trimming the inner and outer anges while remaining in the pressing die.

15. An annular insulating ring comprising concentrically stacked mica discs of unequal diameter formed and compacted into a solid unitary object. o

16. The method of makinglaminated rings which comprises stacking a. plurality of preformed mica discs of difl'erent diameters, heating the discs to render them semiplastic, bending the discs along a line spaced from the circumference thereof to form an outer flange extending obliquely, and finally pressing' the sheets to consolidate them while simultaneously removing a. central portion.

17. The method of making mica insulating rings which consists in bending a heated stac of preformed mica' discs of dlfl'erentsize arranged in concentric relationship along a line spaced from the circumference of thestack to form an outer flange extending obliquely and finally compacting the sheets to consolidate them whereby to cause a flow of mica within the product in order to eflect a uniform distribution of mica in any zone of the product.

18. An annular insulating ring havin two converging integral flanges, said ring being formed from a stack of mica discs including a larger and a smaller disc in such a manner that the larger disc extends in both flan es forming a retaining shell, while the smal er disc extends in the lnner portion of the ring to strengthen and reenforce one of the flanges.

19; The method of making laminated insulating rings, which consists in stackin a plurality of pre-formed mica discs of di erent diameters and bending the discs along a line spaced from the circumference of the largest to form converging flanges, wherein a larger disc extends in both flanges and forms a retaining shell, while a smaller disc extends principally in one flange only, whereby to strengthen the flange.

20. The method of making laminated mica rings, which consists in forming a plurality of discs of different diameter, placin the discs co-axially one above the other and ending the peripheral portions of the stack upwardly from the original plane and simultaneously exerting pressure whereby to consolidate the sheets and compact the peripheral portions by means of pressure exerted edgewise on the peripheral portions.

21. An annular insulating ring comprising concentrically stacked mica discs of unequal size, the discs being formed and compacted strengthen and re-enforce the ring at this point. 7 a

23. The method of making laminated insulating rings which consists in'stackin a plurality of pre-formed mica discs of'di erent diameters and bending the discs along a line spaced from the circumference of the largest to form conver 'ng flanges, wherein a larger disc extends in 0th flanges and forms a retaining shell, while a smaller disc extends in one flange and partially in the other flange at its base to strengthen the ring at the intersection of the flanges.

In witness whereof, I have hereunto subscribed my name.

LOUIS T. FREDERICK. 

